By Nick | Edited by Steve N Updated 27 Mar 2015
Unlocking your phone means you can use any network's Sim card, giving you the freedom to switch providers, lower costs and pass on your phone to others.
Why unlock your phone?
Often networks give away free Sim cards, which can come with free texts or calls. Yet if your phone isn't unlocked, you can't put them in and take advantage. Any decent free Sim offers are included in the free weekly MoneySaving email .
Added handset value
Unlocked phones tend to sell for more on websites such as eBay, because they have much wider appeal to users on other networks and in other countries. Check our eBay selling tricks guide for more information.
Freedom to roam
Unlocking means you can use foreign Sim cards to cut phone costs while you're abroad. See Cheap Roaming for more.
In short, unlocking gives your mobile independence from the network you got it from - and it's usually simple to do. Many older handsets can be unlocked using codes generated free on the web, and if that doesn't work, you can do it for a reasonable fee, either through your network, or high street phone unlockers.
Even if you have to pay your network to unlock the handset, unless you're on a particularly good tariff already, the savings should quickly outweigh the outlay.
Why do mobile phone companies lock phones?
Mobile companies say their phones are already heavily subsidised to entice you to buy them, and they need to make up this shortfall. Yet the reality, as ever, comes down to cold hard cash. For the firms, it wouldn't make sense to sell you the phone at reduced cost, and then let you take your cash to another network provider.
However, it's not all doom and
gloom and some providers, such as Three, have started selling unlocked phones - both to those on pay-as-you-go and pay-monthly contracts.
If you want more info, Ofcom has produced a table detailing the costs of unlocking for each network and the average time it takes.
It's perfectly legal to unlock your phone
It's a common misconception that unlocking your phone is illegal. Unsurprisingly, mobile phone companies aren't keen to dispel this myth. The confusion arises because unlocking and unblocking are often mixed up. They mean different things. In a nutshell:
Unlocking is totally legal
It just means making the phone work with any Sim card.
Unblocking is illegal
This is the practice of making a phone work again after it's been blocked by the networks, usually as a result of its being reported lost or stolen. It's thoroughly illegal and should not be attempted.
What about my warranty?
While it's not illegal, unlocking your phone WILL invalidate its warranty in most cases. So make sure you think twice if you're still in the warranty period and have a super-expensive handset. While it's possible to 're-lock' some phones, you shouldn't rely on this.
Is there any way around it?
It's possible to get a Sim unlocking attachment. It's a little device roughly the same size and shape as a Sim card, which goes in the handset's card slot alongside the Sim itself.
Effectively, the device unlocks your Sim to make it work with the handset, rather than the other way around, so your phone warranty remains intact when you use one - though obviously you can't sell the phone as 'unlocked', because it isn't.
Whilst these claim to unlock most handsets, feedback has been patchy so far. If you've used one, please report your experiences in the Mobile Unlocking discussion.
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